A pedigree is a genealogical graph or table which records the relationship of families by degrees. It is essential to genetic counseling. Drawing a pedigree is regarded as a trained skill of genetic counselors to obey the general rules of pedigree nomenclature [1
]. Genetic counselors usually draw the pedigrees by handwriting or with the assistance of some commonly used drawing software such as Microsoft PowerPoint. This handwriting procedure is usually time-consuming and may lead to a mess when modifying. It will take a lot of time to align the icons and to annotate the pedigree when using drawing software such as Microsoft PowerPoint. In medical records, the family history is required to document and trace the inheritability of certain kind of disease. As the usage of electronic medical files is more popular in medical practice, the inconvenience in drawing a pedigree by hand or by current drawing software precludes the general practitioners from using the electronic files. In medical research, a detailed pedigree is required in genetic mapping or linkage analysis, which calls for a simple tool to draw pedigrees [2
]. More recently, online genetic education and genetic counseling websites have been developed in the Internet era [3
]. This service requires a simple drawing tool for the online genetic counselees without professional training.
To meet the above needs, several tools for drawing a pedigree or record the family history have been developed. Most of them are not web-based and can not be freely online accessible by users (such as the commercial pedigree drawing programs Cyrillic, Progeny) as listed in the category of "Pedigree Drawing Programs/Software Reviews" compiled by a genetic counselor, Debra Collins, at University of Kansas Medical Center, although it is not comprehensive [4
]. A well-designed web tool to document a family history, My Family Health Portrait, is developed by the US Department of Health and Human Services [5
]. As a tool from the US Surgeon General, it is easy to learn by Internet users, but does not output a standardized pedigree used by genetic counselors. It is not user-friendly when inputting multiple family members. Markinen et al. [6
] have developed a high-throughput pedigree drawing tool, which is suitable for large families, but not for a standardized pedigree as recognized by genetic counselors [1
]. Some pedigree drawing or editing program is limited by operating system, such as Madeline [7
] is supported by Linux, Pedigree-Draw [8
] is limited to Macintosh users, while Pelican [9
] is a Java-based software tool. Here we designed a pedigree drawing tool that is online accessible and user-friendly, which can be easily implemented in online genetic counseling or remote medical practice by obeying the general rules of a standardized pedigree nomenclature.